1. Field of the Invention
The present invention relates generally to audio information systems and is more particularly concerned with the use of a microprocessor which receives positional information from a global positioning system receiver and then converts the positional information to a digital format for a voice module which broadcast the information.
2. Description of the Prior Art
In the past a variety of systems have been developed to provide audio information to indicate to the user their position or the position of an object that is being tracked by the user. Most such prior art systems which use audio signals or sound as a means for providing position information are relatively simple in design yet these systems are extremely limited as to their end use.
For example, U.S. Pat. No. 4,490,717 discloses a graphic display device which includes a cassette tape recorder which is provided as a memory to store graphic data of the drive route. The cassette tape recorder includes a track which is used for voice. The content recorder on the voice track is converted to an electrical signal which is amplified by an amplifier and reproduced as a sound signal from a speaker.
U.S. Pat. No. 4,190,819 discloses a motor vehicle audio information system having a programmable automotive tape recorder that can automatically deliver sequential prerecorded messages concerning road information and the like at predetermined intervals. An electromechanical adapter connected to the odometer system of the vehicle provides pulses that are proportional to the distance traveled and these pulses are fed into a microprocessor which performs arithmetic and logic functions to drive a tape recorder with prerecorded messages. The system permits the distance data for programming the microprocessor and the related sequential message to be stored directly on the tape such as a prerecorded cassette or for the distance data to be stored in the memory of the microprocessor with the sequential messages on the tape only.
There are also in the prior art sophisticated audio systems which provide sound or audio information which is indicative of the position of a craft, either on land, sea or in the air being monitored. One such prior art craft tracking system is disclosed in U.S. Pat. No. 5,153,836. The system of U.S. Pat. No. 5,153,836 allows the position of a plurality of craft, either on land, sea or air to be monitored. Each craft determines its own position using an existing position determining system such as a Global Positioning System. Each craft then transmits a radio frequency signal into which position information, preferably identifying information, and other messages, have been encoded. Each craft broadcast its position, identifying information, and other messages on a regular basis without the need for any interrogation signal. The broadcast position and identification information can be received by other craft and, since each craft has determined its own position, can be used to determine the proximity and identity of other craft. An audio alarm system is provided which is integrated with a computer to apprise the operator of a craft of a potential collision or other situation requiring attention.
While each of these prior art sound or audio systems are generally satisfactory for their intended purpose, that of providing position information to a craft either having such a system or tracking another craft which has an audio system for indicating position, these prior art audio systems have certain limitations. For example, such prior art audio devices for indicating position are generally built in to the craft which uses the system. In addition, their cost may be prohibitive preventing their use in, for example, automobiles, pleasure boats and small commercial aircraft.
There are also limitations with respect to the flexibility of these prior art audio or sound systems in that the systems require a predetermined or preprogrammed route to be followed by the craft using the system. Deviation from the preprogrammed route will cause system error resulting in the system being of little or no value to the user.
In addition, a number of these prior art audio or sound systems require a high degree of technical skills to operate thus significantly limiting the number of people who could use these systems.
Accordingly, there is a need for small, relatively simple in design, relatively inexpensive and highly reliable audio system which provides accurate position information to the user of a craft having such a system or the user of a craft tracking a vehicle or target having an audio system for indicating its position.